We report a simple direct route for the synthesis of high-quality semipolar (11 (2) over bar2) AlGaN alloys across the composition range by metalorganic vapour phase epitaxy. We show that a single high-temperature growth step without the use of a low-temperature nucleation or buffer layer is a convenient way to grow high-quality (11 (2) over bar2) AlGaN layers on m-plane sapphire substrate. We also report a detailed investigation of the microstructure and optical properties of these layers including phase-purity, surface morphology, epilayer tilt, and polarization-resolved optical transmission measurements. (C) 2015 Elsevier B.V. All rights reserved.